Question

What important realization does bud have in chapter 18?

Answer 1

In Chapter 18, Bud learns that Herman E. Calloway is his grandfather.

This discovery leads him to have some conflicting feelings. He is confused because he thought that Herman was his father, but he's happy that he's his grandfather. He really likes Herman because Herman is nice to him.
He's also sad because he learns that his mother has died.